Method and apparatus for integrated electric power generation, storage and supply distributed and networked at the same time

ABSTRACT

An electric power retention distribution cell supplies stored electrical power as the primary electric supply to an end user at predetermined times. The cell has a rechargeable battery assembly, a bi-directional inverter and a switch control, and is connected to an electric utility grid, to one or more end users and to alternate power generation sources, such as wind or solar. The battery assembly is charged from the alternate power generation source and from grid power, and the cell is switched at selected times to provide the primary electric supply from stored electric power in the cell to the end user. A circuit of the battery assembly gives an extended electric power storage time by controlling storage parameters. Networks using the electric cell are also described for a utility hub network formed using two or more cells, and for a regional utility hub network formed using multiple utility hubs.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority under 35 U.S.C. 119(e)to U.S. Provisional Application No. 61/459,586 filed on Dec. 16, 2010,the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE

1. Technical Field

The present disclosure relates to systems for electric power generation,storage and distribution.

2. Description of Related Art

Current electric power generation and distribution is centralized. Assuch, large scale power generation and distribution lacks flexibility,resilience and is vulnerable to large scale blackouts and catastrophicregional emergences. These issues are recognized globally. Currentlymany governments (US, Japan, EU, etc.) are sponsoring long-term effortsto resolve these type of issues. The “centralized approach” is also veryinefficient and costly, and hence not feasible, when it comes to energygeneration and storage due to lack of a mature and cost effectivetechnology for large scale applications. A key element in all possiblesolutions lies in the energy storage. Current storage technologies havelimited application to electrical grid system storage because of theirpower limitations, low energy density, and high cost.

Issues of integrated electric power systems and generation, andelectrical battery current regulation systems are known and described,for example, in U.S. Pat. No. 5,764,502 and U.S. Pat. No. 7,589,498 B2.One of the oldest types of storage makes use of the lead acid batterytechnology. While it is used predominantly for cars, this technology isstill evolving and continues to be used in a number of energy storageprojects in the United States. Although lead acid battery technology hasmany advantages, its energy management capabilities are very limited dueto a short life cycle, inconsistent energy delivery, and highmaintenance cost.

A promising candidate for large scale energy storage applications is thesodium-sulfur battery technology which has been tested for electricalgrid applications by, for example, the US Department of Energy. Thisbattery has relatively higher power, energy density, and efficiency.However, it is not feasible for residential and commercial applicationsdue to: (1) operational, safety, and maintenance requirements (operatesat high temperatures about 300° C.); (2) high cost ($3,000 per kilowattinstalled); and (3) the large amount of space it requires. By someestimates a 20 kW system may require a 30 square foot space. Thereforethe application of known methods and systems is heretofore recognized asbeing limited and not applicable to residential/commercial use. (As usedherein, “residential/commercial” means “residential and/orcommercial.”).

SUMMARY OF THE DISCLOSURE

The present disclosure describes a new cost effective and resilientpower system that utilizes the electrical grid and renewable(photovoltaic, wind, etc.) energy generation in conjunction with batterybased energy storage to provide comprehensive and cost effective energysolutions for residential and commercial use. The disclosure presentsand describes distributed energy generation and storage using localizedunits/cells, and then, through an electrical grid, connecting theseunits/cells first into clusters and then into a large scale energynetwork. Advanced battery storage is used for full energy needs fornumerous days. When not in use, the stored energy can be preserved.

In one embodiment of the disclosure, a novel apparatus structure andmethod is proposed for comprehensively addressing issues of localizedpower generation, storage, and distribution in a way that changes theentire approach and concept of having just centralized power generationand distribution. In another embodiment, solutions are provided forelectric power generation, storage and supply for residential andcommercial applications by implementation of the localized concept inconjunction with the use of electric vehicle battery technology that isreadily available.

In one embodiment, the present disclosure utilizes novel connectionconfigurations of used electrical car batteries that still haveexcellent performance for residential/commercial energy storage use.Electrical car batteries generally degrade during the years of serviceand become less efficient for meeting demanding requirements of theautomobile industry, for instance, rapid acceleration with quickdischarging and charging needs. For example, loss of 20% of the batteryperformance level may have significant impact on a vehicle's performanceand safety. However; for the energy storage “static” use (e.g., aresidential use) these batteries still retain much neededcharacteristics.

Additionally, using car batteries for energy storage inresidential/commercial applications makes use of the higher energydensities of such batteries, as the auto industry continues to improvethe stored energy per kg of weight factor to improve the distance avehicle travels per single battery charge. This higher energy densitymakes for more compact residential storage units. The car industry isanticipating improvements in capacity of electric car batteries at about8-10% each year. See, e.g.,http://www.hybridcars.com/news/13-key-questions-and-answers-about-nissan-leaf-battery-pack-and-ordering-28007.htmlfor a description of battery improvements in the context of hybrid cars.If the anticipated improvements are realized, this will further reducebattery weight and increase energy storage capacity. Thus energy storagecapacity for the same size and weight can be expected to double in about8 years. Accordingly, in another embodiment, the disclosure provides adistributed power storage and generation system with high performanceand low energy storage cost by making use of these advancements of theelectric car battery industry in utilizing the huge number of these carbatteries which are available for recycling.

A method and a system are described for energy management by whichenergy is distributed and networked at the same time. This energymanagement encompasses the generation of energy when it is most costeffective, the storage of energy most efficiently, and the availabilityof this lower cost reservoir of energy for use when needed. The systemdescribed is the main power supplier to the end user during theelectrical grid's high load times, and supplied power is replenishedduring the night, at the electrical grid's low load times. The systemand its components combine two critical function-enablers: (1) thedistributed character of power generation and storage using anelectrical cell, and (2) the networking-integrating of all units/cellsas a robust system. Furthermore, due to technological breakthroughs inthe car battery industry, it is feasible to achieve all of theabove-mentioned on a smaller localized scale (residential/commercial)

The various embodiments of the disclosed cost effective and lessvulnerable integrated power systems are characterized in that each iscreated with no single point of failure. They are thus not only costeffective, but also are not vulnerable to a power failure or blackout ofgrid power. The system is replenishing, re-charging and storing energyfrom the grid during low-load (night) times, when grid electricity isless expensive and when renewable sources (e.g., hydro-electrical) areoftentimes able to generate a significant amount of the powerrequirement. (The words “energy” and “power” are used interchangeablyherein). Also, the cell uses all other renewable energy (photovoltaic,wind, geo-thermal, etc.) generated on-site and stores that renewableenergy for later use. “On-site” as used in this context means in thevicinity of the site of the cell or at a reasonable distance therefromfor transporting electrical energy from the renewable energy source tothe cell site. This eliminates the need to send this surplus energy toutilities which requires additional systems and fees. The cell system ismore self-sustained and independent, and can meet all energy needs ofits end users including back-up power for emergencies. The “cell”referred to herein is an electric power retention distribution cell. Forsimplicity in the disclosure it is referred to simply as a “cell” withit understood that it is an electric power retention distribution cellthat also functions to connect the components of the cell and connectthe end users to one or more electrical networks.

In another embodiment of the disclosure, electric power is delivered toan end user, using a cell that comprises a battery assembly operablyconnected to a bi-directional inverter configured to invert AC powerfrom an electric grid to DC power to the battery assembly, and forinverting DC power from the battery assembly to AC power for delivery ofAC power to the end user, and a switch control for disconnecting thegrid from the cell and from the end user at a first time set, and forconnecting the grid to the cell and to the end user at a second timeset. The method comprises connecting the cell with series and parallelconnections to the electric grid, and selectively connecting one of thecell and the electric grid as the electric supplier to the end user.

There is also provided a cell for selectively providing electric energyto an end user comprising a rechargeable stored DC energy storageassembly, a bi-directional inverter connected to the rechargeable energystorage assembly, and a switch control operably connected to theinverter, an electric grid and the end user, wherein the switch controlis configured to connect electric grid energy for delivery to the energystorage assembly and to the end user starting at a first set time, andto disconnect the grid energy from the energy storage assembly and theend user, and connect the energy storage assembly to the end user, at asecond set time.

There is further provided a regional utility network system for deliveryof electrical energy to an end user comprising an electrical gridconfigured to supply electrical grid energy, a regional utility hubconnected to the electrical grid for receiving and distributing theelectrical grid energy from the electrical grid, a utility hub connectedto the regional utility hub for receiving and distributing electricalgrid energy from the regional utility hub, and a cell connected to theregional hub for receiving and distributing electrical energy to an enduser, wherein the cell comprises an energy storage assembly for storingelectrical energy, an inverter connected to the battery assembly forconverting between AC and DC power. A switch connected between theutility hub and the and the inverter unit for selecting between theelectrical grid energy or energy from the energy storage assembly fordelivery to the end user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial illustration of an integrated power system usingthe unit/cell concept to integrate electric power storage and supply;

FIG. 2 is a block diagram of an integrated power system using theunit/cell concept to integrate electric power storage and supply;

FIG. 3 is a block diagram of a cell cluster of an integrated powersystem formed by connecting multiple electric power retentiondistribution cells at a utility hub;

FIG. 4 is a pictorial illustration of a regional integrated power systemformed by multiple cell clusters connected together at a regionalutility hub;

FIG. 5 is a block diagram of a regional integrated power system formedby multiple electric power retention distribution cells connected toutility hubs joined together at a regional utility hub;

FIG. 6 is a schematic diagram of an embodiment for the electricaloperation of an electric power retention distribution cell;

FIG. 7 shows circuit diagrams of series and parallel batteryconnections;

FIG. 8 is a circuit diagram of a battery configuration in one embodimentof the battery assembly;

FIG. 9 is a notional chart showing stored energy depletion over time fordifferent battery voltages;

FIG. 10 is an illustration of battery configurations used under test;

FIG. 11 is a graph showing battery voltage versus SoC from 50% to 100%;

FIG. 12 is a graph of a manufacturer's data for battery capacityretention (%) over time;

FIG. 13 is a graph of change in battery SoC over 30 days;

FIG. 14 is a graph of change in battery SoC over 180 days;

FIG. 15 is a flowchart showing a method of operation of a cell fordelivering power to an end user according to one embodiment; and

FIG. 16 is a flowchart showing a method of operating a battery assemblyof a cell according to one embodiment;

DETAILED DESCRIPTION OF THE DISCLOSURE

Embodiments of the present disclosure will be described in detail withreference to the drawings. In the drawings, parts that are the same orcorrespond to each other have been given the same reference signs, andredundant descriptions thereof will not be given.

Electric car batteries at the end of their automotive life can stillhave about 70 to 80% of their charging capacity when new. Unlike abattery's use in vehicles where conditions are fairly demanding withrapid discharging and charging, a residential/commercial use of the samebattery gives the battery a “second life” once its automotiveapplication is finished. Use of “recycled” batteries also favorably addsto the cost/benefit of the system of the disclosure. The stored energywill meet full energy needs for days and when it is not in use, and canbe preserved, nominally for up to a month, while also being available tomeet any emergency back-up power situation.

Referring now to FIGS. 1 and 2, FIG. 1 is a pictorial illustration andFIG. 2 is a corresponding block diagram of an integrated power system(IPS) according to the disclosure using the unit/cell concept tointegrate electric power storage and supply. The integrated power system10 includes a “cell” (or “unit”) 12 which contain a central controlswitch (CCS) 14 connected to an outside utility electric grid (UEG) 16,and a battery assembly 18 connected bi-directionally to aninverter/charger unit 20. Herein the central control switch is alsosimply referred to as “control switch” and the utility electric grid isat times simply referred to as the “grid.” Inverter/charger unit 20 isconnected also via a bi-directional link to central control switch 14.Inverter/charger unit 20 (“inverter”) functions both as a bi-directioninverter and a charger to battery assembly 18. A power meter 21 isconnected in series with switch control 14 to utility electric grid 16.As used herein, “units/cells” refers to a localized power storage,switching and distribution “unit” or “cell,” one example of which ispresented in FIGS. 1-2. The preferred term “cell” is predominately usedherein for the localized power storage, switching and distributionsystem.

The central control switch is also connected to alternate energy orpower sources 17 (FIG. 2), such as a wind power generator (WPG) 17 aand/or a photovoltaic panel (PVP) 17 b (FIG. 1) via one or moredirectional links to the alternate energy sources. The one or morealternate power sources delivery output power to the battery assembly ofthe cell. An appropriate interface (not shown) could be used with thebattery assembly. As used herein, “energy” and “power”, as in “energysource” or “power source” are used interchangeably. Central controlswitch 14 is also connected via one or more directional links to aresidential and/or a commercial (residential/commercial) end user 22 ofelectric energy. Any number of end users could be connected to the cellas indicated by the dashed lines to end user 23 in FIG. 2. Althoughillustrated as a single additional end user 23, end user 23 canrepresent any number of additional end users connected to cell 12.

FIG. 3 is a block diagram of a cell cluster 24 of an integrated powersystem formed by connecting multiple electric cells 12 a-12 d at utilityhub 26 which is connected to utility electric grid 16. FIG. 3 shows fourdistributed and independent units/cells 12 connected together at utilityhub 26 to form the cluster; however the number of cells is not solimited. Any number of two or more cells could make up a cluster. Therecould be, for example, more than four cells, as indicated by the dashedline cell n designated in FIG. 3 as 12 n. By utilizing one or morecurrent utility grids, all units/cells are networked-integratedtogether.

Referring next to FIGS. 4 and 5, FIG. 4 is a pictorial illustration, andFIG. 5 is a corresponding block diagram, of a regional integrated powersystem formed by multiple cell clusters connected together at a regionalutility hub. The embodiment of FIGS. 4-5 is a system arrangement for aregional utility network using clusters of cells connected togetherthrough utility hubs, and the utility hubs (A-D in the example of FIG.5) joined at regional utility hub 28. The number of clusters joinedtogether at a regional utility hub is not limited to four but canconsist of two or more clusters. This is indicated in FIG. 5 by utilityhub 24 n to show that additional cell clusters can be connected to theregional utility hub. Although not illustrated, the same concept can beextended to a country-wide scale. Thus another embodiment of thedisclosure is its application in providing a vast regional, or acountry-wide, network by interconnecting two or more regional utilityhubs together to form an integrated power system made up of individual,localized electric cells (“cells”).

The systems and components that center on the cell electric storage anddistribution concept work in counter-phase with the utility electricgrid's power demand. During the electrical grid's high load demand(usually during the day time), the cell supplies needed electrical powerto a home or business by use of the stored DC voltage in combinationwith an inverter/charger unit that converts the DC power to AC. Duringthe electric grid's low load demand (usually during the night time),stored electrical power in the cell is replenished also by use of theinverter/charger unit which converts AC power from the grid to DC tocharge the batteries during night time when the electrical grid's loadis usually low and the energy is less costly.

FIG. 6 is a schematic diagram of the electrical operational of anelectric power retention distribution cell (“cell”) 12 in oneembodiment, and provides additional schematic details to the blockdiagram of FIG. 2. In FIG. 6, the cell has a battery assembly (BAA) 18,connected to a bi-directional inverter 20, which connects to centralcontrol switch 14. In one embodiment, the bi-directional inverter israted to handle power from 2.5 to 12 kW.

Central control switch 14, in the embodiment of FIG. 6, contains fourcircuit breakers, 14 a-14 d. Circuit breaker 14 a protects thetransmission circuit for input of electric power from an alternateenergy source at on-site power generation 17 in FIG. 6. Switch 38 a isclosed to allow electric power from one or more on-site power generationsources to be inputted through circuit breaker 14 a to inverter 20. Theelectric power from on-site power generation 17 may be received at thecell as either AC or DC power. Hence, the power inputted through circuitbreaker 14 a is connected to inverter 20 for a determination of whetherthe received power is AC, and if so, the AC is inverted to DC fordelivery to the battery assembly. If the power received from alternateenergy source 17 is DC, then it is delivered as input to the batteryassembly without any inversion.

Circuit breaker 14 b protects the circuit during delivery of AC electricpower, when switch 38 b is closed, from inverter 20 to the residentialor commercial end user 22. If there is more than one end user ofelectrical power in end user 22, then multiple switches 38 b would beused, respectively, for each end user.

Circuit breaker 14 c protects the transmission circuit in the deliveryof utility electric grid power 16 to the end user 22 when switch 38 c isclosed. Switch 38 c can also be closed to allow the grid to provideauxiliary power to the end user, e.g. to power certain controlsdepending on the need of end user 22, even when the cell is serving asthe end user's primary electric supplier. In this case, the end userremains connected to the grid but uses grid power only for auxiliary orback-up power needs while taking its primary electric power supply fromthe electric power retention distribution cell.

Circuit breaker 14 d protects the cell's transmission circuit for inputof utility electric grid power to inverter 20 when switch 38 d isclosed. The utility grid's AC power is inverted at inverter 20 to DCpower and then is inputted to battery assembly 18 to charge thebatteries in the battery assembly. One or more interfacing circuits (notshown) may be included between the inverter and battery assembly.Examples of such interfacing circuits are: a battery charging circuit todeliver a controlled charge current and voltage to the batteries, orother electrical power storage devices, in battery assembly 18; abattery charging control circuit to prevent overcharging and/or othercontrol during the process of charging the batteries; and an impedancematching circuit for minimizing loss between inverter 20 and batteryassembly 18. Such circuits may be included as part of and includedwithin either inverter 20 or battery assembly 18.

Battery assembly 18, while made up of multiple batteries in anembodiment of the disclosure, is not so limited. The battery assemblymay contain any type of electrical storage components, devices and anyparticular arrangement or connections thereof. For example, batteryassembly 18 may contain capacitors, or a combination of capacitors andbatteries, or other electrical energy storage component or device.

Switch 38 e in FIG. 6 is closed to supply auxiliary power, as needed, tothe electric power retention distribution cell and for operation of anyauxiliary power generation supply. For example, auxiliary power can bedelivered from the utility electric grid 16 to operate an alternateenergy source at on-site power generation 17. Auxiliary grid power canalso be delivered to the cell to provide power for operation of any oneof more components of the electric power retention distribution cell, asneeded. For example as shown in FIG. 6, when switch 38 e is closed,electric grid power 16 is delivered as auxiliary power to inverter 20and to battery assembly 18.

An electric power meter (KV2) 21 is inserted in-line as part of the cellto monitor the operation by measuring standard parameters in theindustry, such as power, voltage, and current. Electric power meter 21is connected in series or in parallel, or a combination thereof, withutility electric grid 16 according to standard power meter connectionsas are well known in the industry.

Battery assembly 18 is a battery storage bank with an energy storagecapacity of from 9.6 to 50 kWh. Batteries can be connected together byuse of series battery connections, parallel battery connections, or acombination of series and parallel battery connections. For example,nine 12 VDC batteries can be connected in series to produce an output of108 VDC that is inputted to inverter 20 for inversion to AC power. Inanother arrangement, a set of three 12 VDC batteries can be connected inseries to produce an output of 36 VDC, and then three such sets beconnected in series to also produce an output of 108 VDC. It should benoted that configurations may include more than three batteries, and insome circumstances, may be two batteries, depending on the nature of thebatteries themselves.

In operation, the cell is set to time its connection and disconnectionto the end user to supply and not supply, respectively, electrical powerto the end user so to reduce or minimize electric power cost to the enduser. For example, at a first predetermined time in the evening or nighttime (the first “set time”), the control switch 14 connects the cell tothe grid (UEG) by closing switch 38 d. This causes delivery of gridelectric energy to inverter 20 which converts the AC grid power to DCand delivers DC electricity at the inverter's output to charge thebatteries in the battery assembly. DC electricity is thus stored in thebatteries of the battery assembly during the time that the cell isconnected to the grid through switch 38 d. At a second predeterminedtime in the morning (second “set time”), with the batteries in thebattery assembly being fully charged, control switch 14 disconnects thegrid by opening switches 38 c and 38 d and connects (in series) the cellto the end user by closing switch 38 b. In this stage, the cell is themain energy supplier to the end user, as DC power stored in batteryassembly 18 now flows to inverter 20 where it is converted to AC powerand delivered through closed switch 38 b to the end user 22. In thissituation, switch 38 c can optionally also remain closed to provideauxiliary power to the end user if desired.

In case of equipment failure or battery depletion (detected byappropriate monitoring devices, not shown), the control switch connectsthe grid to the residence or commercial entity and restores regular gridpower supply to the end user by closing of switch 38 c and opening ofswitch 38 b. During the day and/or night, the cell, and specifically itsbattery assembly 18, can also be charged by using available alternativeenergy sources 17, such as solar (photovoltaic cells), wind, orgeothermal power generators, by closing switch 38 a. These alternativeenergy sources are referred to as “on-site power generation,” whichencompasses alternate power generation sources in the vicinity of thecell or within a reasonable power transportation distance to the cell.Switch 38 e may be closed during either or both of the first and secondset times to provide auxiliary power from the grid to the on-site powergeneration of the alternate energy source, which may consist of one ormore alternate energy source, to the inverter 20 and to battery assembly18.

The control switch and its individual switches may be controlled by amicroprocessor, a computer, or by other automated devices. For example,an operator could input into a computer desired first and second settimes for designating when the grid or the cell is to be the primaryelectric supplier to the end user.

It is understood that, although not shown in the figures, standardelectrical meters, using either a series or parallel connection asappropriate, circuit breakers, and other devices as used in the deliveryand receipt of electrical power could be included in the schematiccircuit diagram of FIG. 6 and in connecting the cell to other parts ofthe described integrated power system.

Battery Configuration

Battery assembly 18 stores the electrical energy of the cell fordistribution to one or more end users at preselected times. FIG. 7 showsthe basic arrangements for series and parallel connections of multiplebatteries. FIG. 7(A) is a circuit for a series connection of nine 12volt (12 VDC) batteries to give an output voltage of 108 VDC. FIG. 7(B)is a circuit for a parallel connection of three sets of three 12 voltbatteries connected in series to give an output voltage of 36 VDC. FIG.8 is an illustration of one embodiment of a battery arrangement in thebattery assembly. The figure shows a battery scheme that utilizes acombination of series and parallel battery configuration, similar toFIG. 7(B), in connecting battery configurations 81 a through 81 i asindicated by the circuit of FIG. 8. Each battery configurationdesignated as 81 a through 81 i consists of or comprises three 12 VDCbatteries connected in series so that each configuration provides 36 VDCof voltage across its outputs. For simplicity, the threeseries-connected batteries in each configuration are not individuallyshown and instead are represented by the respective blocks 81 a through811. Additional batteries may be connected. Relay switches (S) 83 a-83 fare added in the circuit as indicated in FIG. 8 and function todisconnect certain of the batteries 81 a-81 i as illustrated in order tostore and preserve energy for a longer period of time (nominally for upto a month), and to connect the batteries when the stored energy is usedas the primary power supply to the end user. In the battery arrangementcircuit of FIG. 8, the voltage at the output terminals of the batteryassembly 18 (FIG. 6) with relay switches 83 a-83 f closed is 108 VDC.The voltage level at the output of battery assembly 18 can be achievedby use of different battery connection configurations. The batteryscheme of FIG. 8 is shown as one embodiment of a battery arrangement.

Turning next to FIG. 9, a notional chart is presented of stored energydepletion over time for different battery voltages of 36 VDC and 108VDC. The two energy depletion graphs in FIG. 9 are for demonstrativepurposes; that is, they are based on predicted figures. Energy leaksthat cause energy depletion for a given voltage depend on a number offactors. There are internal leaks, leaks though air (due to humidity,temperature, temperature cycling, etc.), and surface leaks (due tomoisture, dust deposits, temperature, etc.). Each of the factors willdepend on actual battery types, assembly configuration and voltage. Forexample, electric car battery assemblies usually operate at highervoltages (e.g., 300-440V). At the higher voltages, external leaks inreal-word conditions can increase significantly during the time. FIG. 9gives an estimated predicted performance of battery energy storage usingassumptions to approximate real world conditions made for variousinternal and external battery leakage factors. The graphs show greaterstored energy depletion over 30 days when the battery level is stored at108VDC and a lesser depletion, hence more favorable results, when thebattery level is stored at the lower 36VDC.

Electrical use for U.S. households is 110 VAC. The use of an inverter toconvert DC voltage to AC voltage, and the use of transformers toincrease or decrease voltage to match residential/commercial use createadditional energy losses. Having a minimal difference in the level ofthe inputted DC voltage to an inverter from the desired output ACvoltage is beneficial in that it minimizes energy loss in the inversionprocess, and thus matching the input/output voltages is most desirable.Optimal results are therefore realized with a 108 VDC output frombattery assembly 18.

However, to store energy in batteries for a long time (e.g., 30 days)and decrease energy losses during this time due to “leaks” (e.g.,surface/air discharge and self/internal discharge), a lower voltage(than 110VDC) will help greatly to preserve the energy, as FIG. 9 shows.Thus, to decrease losses during storage, storing the batteries at themore favorable 36VDC level, as is accomplished by the circuit of FIG. 8,will extend energy storage over time when the cell is not in use. Thedesign in one embodiment utilizes the combination of series and parallelbattery configurations as shown in FIG. 8 where the S-relay switchesselectively disconnect batteries in order to store and preserve energyfor the longer time of up to a month.

Test Description:

Two sets of batteries, each consisting of nine 12v batteries, wereassembled as shown in FIG. 10. In the first set (FIG. 10(A)), only 3batteries were connected in series to form a group, and the three groupswere disconnected from one another. This formed three 36V DC units. Inthe second set (FIG. 10(B)), all batteries were connected in series toform a single 108 V DC unit. All batteries were charged to identicallevels and then disconnected from the charger and kept in the sameenvironment and conditions for 30 days. During that time measurementswere taken of the stored energy in each set at the end of every 10-dayperiod by measuring voltage and current. At the end of the 30-day periodthe 3 group 36 V batteries of the first set were connected in series toachieve 108V DC output unit, similar to that of the second set. Then,the total residual stored energy was measured in both sets. This alloweda comparison to be made of the performance for energy storage of the twosets of nine 12 V batteries. The test information that follows will showthat actual tests conducted confirm the notional chart performance shownin FIG. 9.

Battery Assembly State of Charge Test Results.

Determining the State of Charge (SoC) of a battery is a key factor forbattery quality control in all applications. SoC as an indicator ofstored energy is measured using methods accepted by the industry. See,for example, “Methods for State-of-Charge Determination and theirApplications”, Sabine Piller et al., Journal of Power Sources, 2001, pp.113-120. Long term energy storage testing typically uses type PS-1250batteries. An exemplary SoC graph is presented in FIG. 11 which plotsbattery voltage as a function of its SoC in showing the relationshipbetween a battery's open circuit voltage and its SoC. Use of this graphhelps to accurately determine changes in battery electrical chargelevels over time by measuring open circuit voltage. In view of this andother battery quality control advances, battery operation is currentlychanging to what could more accurately be called battery management thansimply battery protection.

To determine the best battery configuration for the battery assembly 18of cell 12, tests were conducted to determine the battery's retention ofits electric charge using different configurations. SoC was measured forpurposes of this disclosure using methods accepted by the industry.

A standard 12 volt, lead acid battery was used. Specifically theinventor used a “Power Sonic” battery model PS-1250F1 manufactured byPower-Sonic Corporation in San Diego, Calif., rated at 12 volt and 5.0amp-hr. This specific type of battery was used for demonstration andproof of concept purposes. While the actual results (numbers of SoC) formetal ion batteries may vary, the concept for an optimal set ofbatteries as described will still apply.

Two battery configurations were tested. In one configuration, nine 12volt batteries were connected in series to give an output of 108 VDC, asillustrated in FIG. 10(B). In the other configuration, nine 12 voltbatteries were connected in series in groups of three, and the threegroups then connected in parallel, to give an output of 36 VDC of eachgroup, as illustrated in FIG. 10(A). Both configurations (A) and (B)were left open circuited for purposes of the test. Each time eachbattery of FIGS. 10(A) and 10(B) was disconnected from any load for itsSoC measurement, that it, an open circuit measurement was made. The testenvironment was controlled and maintained. The temperature was at 63 F,and humidity at 28-30%. The resulting plot of data is as shown on thegraph of FIG. 11, which plots the open circuit voltage of the batteryversus its SoC, where the data points are the average of themeasurements made on each of the nine batteries. FIG. 11 shows that atthe start point where the battery is 93% charged its starting voltage isapproximately 12.85 VDC. As the battery charge decreases over time, itsopen circuit voltage decreases rather linearly down to approximately12.05 volts at a 50% charge level (with appropriate extrapolation doneon the graph).

The tests were conducted using three sets of battery assembly: set #1consisted of nine 12 VDC batteries connected in series (FIG. 10 (B)) togive a nominal 108 VDC at the output terminals; set #2 consisted ofthree 12 VDC batteries connected in series in three groups, and thethree groups were connected in parallel (FIG. 10 (A)) to give a nominal36 VDC at the output terminals; set #3 was a control set consisting ofone 12 volt battery.

FIG. 12 presents the manufacturer's data of its battery's capacityretention during the storage time standing period of from 0 to 20 monthsfor different temperatures from 41 F-104 F.

Test Results

In “real-world” conditions and environment, energy stored in a batterycan change/deplete due to internal leaks and external conditions(humidity, moisture dust, temperature, etc.). Internal battery leakageis recognized in the industry at about 5%. The external leakage can bestudied ideally with control of outside factors, such as temperature,humidity, etc. External factors were controlled in the actual testsconducted the results of which are presented in FIGS. 13-14 and theseconfirm the predictions of FIG. 9. One set of actual test results areshown in the graph of FIG. 13, which plots data, again from the averagetaken of measurements at the output terminals of the three sets undertest, SoC over a standing time of from 0 to 30 days. The test resultsshow that there were appreciable differences in state of charge betweenbattery assembly sets 1 (9×12V) and 2 (3×12V). However, there was nodifference observed between set 2 (3×12V) and control set 3 (1×12V). Theconclusion is that set 2 (36V) is optimal for longer term energystorage. The experiment proves that even in a well-controlledenvironment (best case scenario), stored energy will deplete differentlybased on the battery set configuration. In particular, the test confirmsthat it is important to disconnect units so to store the energy in thebatteries at the lower (36V) DC voltage to achieve greater energystorage (less loss) for a longer period of time (30 days).

The same test was extended to a longer standing time (storage time) of 6months, and the graph of FIG. 14 shows these results. This longer termtest shows that sets #2 (3×12V) and #3 (1×12V) after 180 days, have verysimilar states of charge, yet the SoC for set #1 (9×12V batteries) ismuch less. This is consistent with the results of the shorter 30-daystorage time test. Both tests thus establish that by switching to 36Vbattery sets, these 36V sets will preserve stored energy on the samelevel as a single battery unit. The important lesson from the test isthat, when in longer term storage, dividing the battery assembly intosmaller open circuit voltages (⅓ of the total voltage to be used) willdecrease the internal leak of energy from the batteries.

FIG. 15 shows a flow chart for a method of operating a cell fordelivering power to an end user such as shown in the embodiment of FIGS.2 and 6. In step S 1501, a cell is formed with a central control switchhaving a plurality of switches, a bi-directional inverter and a batterassembly operationally connected together such as, for example, shown inFIG. 6. In step 1503, the cell is electrically connected to an electricutility grid, to an alternate power supply and to an end user. Thealternate power supply could be one or more alternate power supplies,such as generated by wind power, hydro-electric power or photovoltaiccells. The alternate power supply could be one or more of thesecombinations of alternate power supplies. The end use could be one ormore end users of electricity.

In step S 1505, a selection is made as to whether or not to deliverpower form the primary supply, which in this embodiment is from theelectric utility grid, to the end user. If the primary supply orsupplier is selected, the method proceeds to step S 1507 which connectsto the end user. If the primary supply is not selected, the methodproceeds to step S 1508 where another selection is made at step S 1511.Here the selection is whether to store the batteries, and specificallyto store the charge of the batteries that make up the battery assembly,or to charge the batteries in the battery assembly, or to connect thebattery assembly as the primary power supply to the end user. If theselection is to store the charge of the batteries in the batteryassembly, an appropriate connection is made by the cell's centralcontrol switch to connect or disconnect selected groups of batteries inthe battery assembly to the battery assembly's storage state, asindicated at step S 1515. It is understood that the central controlswitch can be connected to a computer or microprocessor for switchactivation, and also that timers could be used to automate further thetiming and manner in which the central switch control is to be operated.

If the selection is made to charge the batteries, then an appropriateswitch control is activated to connect a power charging supply to thebattery assembly to charge the batteries in the battery assembly asindicated at step S 1509. The power charging supply could include theelectric utility grid power and/or power from other alternate powersources, such as wind and photovoltaic power sources as mentioned above.The alternate power sources or the electric utility grid power sourcecan be used individually, in combination, or selectively along or incombination used any power charging supply. If the selection is to usethe battery assembly as the primary power supply to the end user, theappropriate switching connections are made to connect the batteryassembly to the end user as indicated at step S 1513. The cell'sbi-directional inverter is used when charging the battery assembly fromthe power charging supply by inverting AC power to DC power for deliveryto the battery assembly. The cell's bi-directional inverter is also usedwhen the battery assembly is selected as the primary power supply to theend user by inverting the DC battery assembly power to AC power fordelivery to the end user.

FIG. 16 shows a flowchart for a method of operating a battery assemblysuch as used in an embodiment of the cell. In step S 1601, a batteryassembly is formed by connecting batteries together. The connectioncould be a series connection or a parallel connection of batteries. Itcould also be a combination of series and parallel connections of groupsof batteries. In step S 1603, one or more switches are installed atpredetermined locations in the battery assembly so to connect anddisconnect batteries or groups of batteries. For example, multipleseries connections of batteries could form battery groups, and a switchor switches can be used to connect or disconnect the groups ofbatteries. In one embodiment, groups of batteries are disconnected byactivation of the one or more switches when the battery assembly is instorage and not being used for delivery of power to the end user, andare connected by activation of the one or more switches when the batteryassembly is being used for changing of the batteries from an outsidepower charging supply source, or for delivery of electric power to theend user.

In step S 1605, a selection is made as to whether or not the batteryassembly is to be used to supply electric power as the primary supplierto the end user. If the battery assembly is selected to be the primarysupplier, the battery assembly is appropriately switched so that theoutput of the battery assembly is connected to the end user, asindicated at step S 1607. The DC voltage of the battery assembly may beconnected to an inverter to invert the DC voltage to AC voltage fordelivery to the end user. Since the inverter is a component separatefrom the battery assembly, it is not shown in FIG. 16, but the line of S1607 would connect to the inverter in routing the electric power of thebattery assembly to the end user. It is understood that there could bemore than one end user.

If the battery assembly is not selected to be the primary supplier, thebattery assembly is appropriately switched so that the process proceeds,as indicated by step S 1608, to the next step S 1611 where a selectionis made as to whether the battery assembly is to be charged or stored.If the battery assembly is to be charged, the battery assembly isappropriately switched to connect to an outside power charging supply asindicated at step S 1609. The outside power charging supply could befrom alternate energy sources, such as photovoltaic cells, wind turbinesor hydro-electric generators. The power charging supply could also befrom the electric utility grid. Any one of these exemplary energysources or any combination of alternate energy sources can be used asthe power charging supply of FIG. 16 to charge the battery assembly. Inone embodiment, the switching in of a power charging supply can beautomated, for example by connecting a voltage level detector to thebattery assembly, and when the voltage level at output terminals of thebattery assembly drop below a preset level, then the battery assembly isautomatically switched to connect to the power charging supply. Inanother embodiment, power from an alternate energy source, such asphotovoltaic cells or wind turbines which generate electricity only incertain conditions (the presence of sunlight or wind, in the twoexamples given), could be connected to an energy storage device as partof the battery assembly. Such an energy storage device could be, forexample, a capacitor or bank of capacitors, and the battery assemblythen selectively connected to that energy storage device when thebattery assembly is to be charged.

If the selection is made to store the charge of the batteries in thebattery assembly, then the battery assembly is appropriately switched sothat the outside power charging supply is not connected and thebatteries are stored as indicated at step S 1613 in an open circuitstate. In one embodiment, when switched to the storage state, one ormore switches in the battery assembly are activated to groups ofbatteries connected together where each group has an output terminalvoltage that is less than the output voltage of the battery assemblywhen all the batteries are connected together.

Note that the processes or method steps included in FIGS. 15 and 16 andthe descriptive text associated therewith do not have to be performedchronologically in the order described in the flowcharts. Some of theprocesses may be performed in a parallel manner or may be performed as asub-routine.

The disclosure explains how residential or commercial distributedgeneration and storage can be networked through utilities. This willease the stress on electrical grid during peak times. Furthermore, ifregulated and controlled correctly, use of the cell concept will providemuch needed power storage ballast for the electric utility grid so toreduce or possibly eliminate crashes/blackouts. After scaling to asignificant number of systems participating in the network (achieving acritical mass), the integrated and distributed character of thisdisclosure can at the same time add robustness and redundancy which canwithstand large scale/regional emergencies. Hence, theresidential/commercial power generation and storage capability is acritical enabler to achieve a robust and sustainable energy system.FIGS. 4-5, as previously discussed, presents an example of howdistributed and independent cell sites can be used together to form acell cluster through a utility hub, which can then connect to otherclusters through a regional utility hub to create a regional orcountry-wide network. This concept allows localizing poweremergencies/outages and eliminating a network-wide cascade/domino effectby restricting any such adverse event to a predefined regional level.

The embodiments disclosed in this application are to be considered inall respects as illustrative and not limiting. The scope of thedisclosure is indicated by the appended claims rather than by theforegoing description, and all changes which come within the meaning andrange of equivalency of the claims are intended to be embraced therein.

1. An electric power retention distribution cell for selectivelyproviding electric power to at least one end user comprising: a) arechargeable battery assembly; b) a bi-directional inverter connected tothe rechargeable battery assembly; c) a switch control operablyconnected to the inverter, to an electric utility grid, to a powercharging supply and to the end user; wherein the switch control isconfigured to selectively switch between the electric utility grid andthe battery assembly of the cell as the primary electric power supply tothe at least one end user.
 2. The electric power retention distributioncell according to claim 1, wherein the switch control is configured toselectively switch the battery assembly between a battery assembly usemode and a battery assembly storage mode.
 3. The electric powerretention distribution cell according to claim 2, wherein the switchcontrol is configured to selectively switch the cell to connect to anoutside power charging supply when in the storage mode.
 4. The electricpower retention distribution cell according to claim 1, wherein theinverter is configured to convert an AC electric grid power to a DCpower and output the DC power to the battery assembly.
 5. A method forsupplying electric power to at least one end user using an electricpower retention distribution cell that comprises a rechargeable batteryassembly operably connected to a bi-directional inverter for inverting afirst AC voltage from an electric utility grid to a first DC voltage tothe rechargeable battery assembly, and for inverting a second DC voltagefrom the rechargeable battery assembly to a second AC voltage fordelivery to the at least one end user, and a switch control forselectively controlling circuit connections of the electric powerretention distribution cell, the method comprising: a) connecting theelectric power retention distribution cell to the electric utility grid,to the at least one end user and to a power charging supply; b)providing at a first time set for the electric utility grid to be aprimary electric supplier to the at least one end user; c) switching ata second time set for the electric power retention distribution cell tobe the primary electric supplier to the at least one end user; d)charging the batteries in the battery assembly at a first predeterminedtime from the power charging supply; and e) storing at a secondpredetermined time an electrical power of the battery assembly at athird DC voltage different from the second DC voltage.
 6. The methodaccording to claim 5, wherein the second DC voltage is between 100 and115 volts DC, and the third DC voltage is lower than the second DCvoltage.
 7. The method according to claim 5, wherein the storing of theelectrical power of the battery assembly further comprises: a) dividingthe battery assembly into groups of batteries; and b) disconnecting thegroups of batteries from the battery assembly when storing theelectrical power of the battery assembly, wherein at least one group isstored at the third DC voltage.
 8. The method according to claim 5,wherein the charging of the batteries in the battery assembly comprises:a) converting electric power from the power charging supply from an ACvoltage to a DC voltage; and b) inputting the DC voltage to a chargerunit for supplying charging electrical power to the battery assembly. 9.A utility network for delivering electric power to end users comprising:a) an electric utility grid configured to supply electric grid power; b)a utility hub connected to the electric grid for receiving anddistributing the electric grid power; and c) a plurality of electricpower retention distribution cells connected to the utility hub forreceiving and distributing electric power to the end users, wherein eachcell comprises: 1) a rechargeable battery assembly; 2) a bi-directionalinverter connected to the rechargeable battery assembly; 3) a switchcontrol operably connected to the inverter, to an electric utility grid,to a power charging supply and to at least one end user; wherein theswitch control is configured to selectively switch between the electricutility grid and the battery assembly of the electric power retentiondistribution cell as the primary electric power supply to the at leastone end user.
 10. A regional utility network system for deliveringelectric power to end users comprising: a) an electric utility gridconfigured to supply electric grid energy; b) a regional utility hubconnected to the electrical grid for receiving and distributing theelectric grid power from the electric grid; c) a plurality of utilityhubs each connected to the regional utility hub for receiving anddistributing electrical grid power from the regional utility hub; and d)a plurality of cells connected to each of the plurality of utility hubsfor receiving and distributing electric power to end users, wherein eachcell comprises: 1) a rechargeable battery assembly; 2) a bi-directionalinverter connected to the rechargeable battery assembly; 3) a switchcontrol operably connected to the inverter, to an electric utility grid,to a power charging supply and to at least one end user; wherein theswitch control is configured to selectively switch between the electricutility grid and the battery assembly of the cell as the primaryelectric power supply to the at least one end user.
 11. A batteryassembly with an output voltage comprising batteries for storingelectric power and supplying the stored electric power when connected toa load comprising: a) a plurality of connected batteries formed bygroups of batteries each of said groups having an output terminalvoltage; b) at least one switch connected between at least one of thegroups of batteries and other batteries in the battery assembly; whereinthe at least one switch is adapted to disconnect the at least one of thegroups of batteries when the electric power of the battery assembly isin storage, and to connect the at least one of the groups of batterieswhen the electric power of the battery assembly is connected to theload, wherein the output voltage of the battery assembly when connectedto the load is greater than the terminal voltage of the at least onegroup of batteries when in storage.
 12. The battery assembly of claim11, wherein the groups of batteries comprise a group formed by a seriesconnection of batteries.
 13. The battery assembly of claim 11, whereinthe groups of batteries comprise groups formed by at least one seriesand at least one parallel battery connections.
 14. The battery assemblyof claim 11, wherein the battery assembly is operatively connectable toan outside power supply source for charging the battery assembly and theat least one switch is adapted to be closed to connect the groups ofbatteries together when the batteries of the battery assembly are beingcharged from the outside power supply source.
 15. The battery assemblyof claim 11, wherein the battery assembly is operatively connectable toan inverter for converting a direct current voltage of the batteryassembly to an alternating current voltage when the battery assembly isoperatively connected to the load.
 16. The battery assembly of claim 11,wherein the at least one switch is controlled by a computer.
 17. Thebattery assembly of claim 11, wherein the load is at least one end userof the electric power from the battery assembly.